fix(ci): run required fuzz check in merge queue

[IanHollow]

Why

Branch protection requires the fuzz job, but the trusted merge queue dispatcher omits fuzz.yml. Queue entries admitted with GITHUB_TOKEN do not emit a merge_group workflow event, so the queue commit can wait indefinitely for that check.

Change

• Dispatch the fuzz workflow on the exact queue commit through the existing trusted queue action.
• Notify the reconciler when that dispatched fuzz run completes.
• Include fuzz completion in the reconciler's workflow triggers.

Validation

git diff --check and workstation-task nix develop --command bash scripts/check.sh passed (91 Python tests plus workflow validation). Pull request checks and the protected merge queue will validate the workflow behavior. This change uses the existing pinned queue-completion action and keeps its narrow actions: write permission.